Syromyatnikov M Y, Kiryanova S V, Popov V N
Department of Genetic, Cytology and Bioengineering, Voronezh State University, 1 Universitetskaya pl., Voronezh, 394018, Russia.
Innovative Center "Biruch-NT", EFKO Group of Companies, Malybykovo, 1 Belaya Vezha Str., Belgorod Region, 309927, Russia.
AMB Express. 2018 Nov 22;8(1):186. doi: 10.1186/s13568-018-0716-y.
Food spoilage and its contamination with yeast and mold is a serious problem of food industry. Despite the high fat content, mayonnaise is an attractive substrate for food spoilage microorganisms. The aim of this study was to develop a method for yeast identification in mayonnaise and to test commercially available mayonnaises for the presence of these contaminating microorganisms. Based on the sequencing of intergenic regions ITS1 and ITS2, we identified a yeast microorganism that causes mayonnaise spoilage. We found that DNA sequences were more than 99% identical to the GenBank DNA sequences from Pichia kudriavzevii. We developed a specific to P. kudriavzevii TaqMan probe and primers. The reaction conditions were optimized regarding to the components concentration and temperature cycle. The minimum amount of P. kudriavzevii DNA that could be detected by developed method was 50 fg. The minimal number of P. kudriavzevii cells that could be detected by developed method without pre-enrichment was 50. We tested verified method with DNAs from microorganisms of different taxonomic groups that were obtained from three collections of microorganisms. Finally, we analyzed 20 different brands of mayonnaise from 14 producers and 10 different brands of mayonnaise sauce from seven producers. We determined the Cq parameter that characterizes transition of the fluorescence curve to the logarithmic phase and, therefore, correlates with the extent of sample contamination with P. kudriavzevii yeast. P. kudriavzevii was detected in six analyzed samples of mayonnaise and one sample of mayonnaise sauce.
食品腐败及其被酵母和霉菌污染是食品工业中的一个严重问题。尽管蛋黄酱脂肪含量高，但它仍是食品腐败微生物的理想基质。本研究的目的是开发一种鉴定蛋黄酱中酵母的方法，并检测市售蛋黄酱中这些污染微生物的存在。基于基因间隔区ITS1和ITS2的测序，我们鉴定出一种导致蛋黄酱腐败的酵母微生物。我们发现其DNA序列与库德里亚夫齐毕赤酵母（Pichia kudriavzevii）的GenBank DNA序列相似度超过99%。我们开发了一种针对库德里亚夫齐毕赤酵母的TaqMan探针和引物。对反应条件的成分浓度和温度循环进行了优化。所开发方法能够检测到的库德里亚夫齐毕赤酵母DNA的最小量为50 fg。所开发方法在不进行预富集的情况下能够检测到的库德里亚夫齐毕赤酵母细胞的最小数量为50个。我们用从三个微生物保藏中心获得的不同分类群微生物的DNA对验证后的方法进行了测试。最后，我们分析了来自14个生产商的20个不同品牌的蛋黄酱以及来自7个生产商的10个不同品牌的蛋黄酱沙司。我们测定了表征荧光曲线向对数期转变的Cq参数，因此该参数与样品被库德里亚夫齐毕赤酵母污染的程度相关。在6个分析的蛋黄酱样品和一个蛋黄酱沙司样品中检测到了库德里亚夫齐毕赤酵母。
